There are many microwave power divider/combiner devices known in the art today. One example is the single ring rat-race hybrid magic-tee. This rat-race hybrid magic-tee device has the disadvantage of a relatively narrow, 10% to 15% frequency bandwidth.
The waveguide magic-tee is characterized by its bulky size, and requires complicated machining in the fabrication of the device.
Another device is the branchline coupler with 90 degree transmission line. This device typically has a relatively narrow 5% to 12% frequency bandwidth and is sensitive to dimensional tolerance.
Another power combiner/divider device is the airline/stripline magic-tee as described, for example, in U.S. Pat. No. 4,952,895. This device requires multi-layer construction.
Proximity couplers, e.g., the DuHammel coupler and the quadrature coupler with Schiffman's phase shifter, typically require precision front to back alignment for double sided etching of conductor patterns sensitive to material tolerances.